You should not take a resveratrol supplement unless it has been explicitly recommended for you by your doctor. Taking resveratrol while also using blood thinners, aspirin, or warfarin, could cause side effects. If you have a blood condition, or are pregnant, or breast feeding resveratrol may not be right for you to take as a supplement at this time. Also, if you have an illness that is affected by estrogen production, such as breast cancer, speak to your doctor before taking this as a supplement. Tell your doctor about any medications, vitamins, herbal supplements, or dietary choices you are currently making so that they can decide if resveratrol is currently safe for you. If you allergic to any of the foods that contain this compound or any ingredients of the resveratrol supplement please do not use them, as an allergic reaction could cause great harm to you.